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Auteur Pamela S. Soltis (1957-) |
Documents disponibles écrits par cet auteur (4)
Affiner la rechercheMolecular evidence for polyploid origins in Saxifraga (Saxifragaceae) : the narrow arctic endemic S. svalbardensis and its widespread allies / Christian Brochmann in American Journal of Botany, 85 (7) (07/1998)
Titre : Molecular evidence for polyploid origins in Saxifraga (Saxifragaceae) : the narrow arctic endemic S. svalbardensis and its widespread allies Type de document : Imprimé Auteurs : Christian Brochmann (1953-) ; Xiang ; Brunsfeld ; Douglas E. Soltis (1953-) ; Pamela S. Soltis (1957-) Année de publication : 1998 Article en page(s) : 135-143 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Variabilité, analyse de l'ADN, polymorphisme Mots-clés : Saxifraga Saxifraga svalbardensis Résumé : The recently described polyploid Saxifraga svalbardensis is endemic to the arctic archipelago of Svalbard. We investigated relationships among four closely related species of Saxifraga in Svalbard and tested three previously proposed hypotheses for the origin of S. svalbardensis: (1) differentiation from the morphologically and chromosomally variable polyploid S. cernua; (2) hybridization between the diploid S. hyperborea and S. cernua; and (3) hybridization between the tetraploid S. rivularis and S. cernua. Fifteen populations were analyzed using random amplified polymorphic DNAs (RAPDs) and nucleotide sequences of the chloroplast gene matK and the internal transcribed spacers (ITS) of nuclear ribosomal DNA (rDNA). RAPD and matK data suggest that S. svalbardensis has originated from a hybrid with S. rivularis as the maternal parent and S. cernua as the paternal parent, possibly a single time, whereas ITS data could not be used to discriminate among the hypotheses. The data also suggest that the diploid S. hyperborea is a progenitor of the tetraploid S. rivularis. The four populations examined of S. svalbardensis were virtually identical for RAPD and ITS markers, whereas S. cernua showed high levels of variation, suggesting that the latter polyploid either has formed recurrently or has undergone considerable differentiation since its origin. Identifiant : DOI : 10.2307/2446562 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=138291
in American Journal of Botany > 85 (7) (07/1998) . - 135-143Brochmann, Christian (1953-), Xiang, Brunsfeld, Soltis, Douglas E. (1953-), Soltis, Pamela S. (1957-) 1998 Molecular evidence for polyploid origins in Saxifraga (Saxifragaceae) : the narrow arctic endemic S. svalbardensis and its widespread allies. American Journal of Botany, 85(7): 135-143.Documents numériques
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Article (1998)URL
Titre : Phylogenic relationships in tribe Cardueae (Asteraceae) based on ITS sequences Type de document : Imprimé Auteurs : Alfonso Susanna de la Serna (1955-) ; Núria Garcia-Jacas ; Douglas E. Soltis (1953-) ; Pamela S. Soltis (1957-) Année de publication : 1995 Article en page(s) : 1056-1068 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Phylogénie (liens existant entre espèces apparentées)
[CBNPMP-Thématique] Variabilité, analyse de l'ADN, polymorphismeRésumé : The Cardueae pose vexing systematic problems at several taxonomic levels. Tribal delimitation is controversial, with views ranging from a broadly defined Cardueae comprising subtribes Echinopsidinae, Carlininae, Carduinae, and Centaureinae to a more restrictive Cardueae (comprising only Carduinae and Centaureinae) with tribal rank also given to Echinopsideae (or Echinopeae) and Carlineae. Furthermore, the circumscription of groups within a broad Cardueae is also controversial, with divergent views emphasizing differences in floral or achene morphology; the distinction between Carduinae and Centaureinae is particularly weak. The generic limits of Centaurea, comprising 500–600 species and great diversity in both chromosome number and pollen morphology, are also unclear. Patterns of morphological, chromosomal, and pollen diversity in Centaurea do not completely support either the current taxonomy or any of the proposed modifications. Clearly, the Cardueae in general and Centaurea in particular require a phylogenetic approach to resolve problems of taxonomic circumscription and rank and to understand patterns of pollen and chromosomal evolution. We therefore analyzed DNA sequences of the internal transcribed spacers (ITS) of the nuclear ribosomal RNA genes (rDNA) of 35 taxa to reconstruct the phylogeny of Cardueae and assess 1) the positions of Echinopsidinae and Carlininae, 2) the circumscription of the Carduinae-Centaureinae complex, and 3) the limits of Centaurea and related genera. Phylogenetic analysis of ITS sequence variation strongly supports the monophyly of Cardueae relative to outgroup taxa from Mutisieae and Cichorieae. Both Carlininae and Echinopsidinae occupy basal branches in Cardueae. Carduinae are paraphyletic, forming a basal grade in the tribe. The Centaureinae, however, form a well-supported clade. As typically circumscribed, Centaurea is paraphyletic, comprising species of several other genera in addition to those currently recognized as Centaurea. Proposed evolutionary trends in pollen morphology and, to a lesser extent, base chromosome numbers are largely supported by the ITS phylogeny for Cardueae. Identifiant : DOI : 10.1002/j.1537-2197.1995.tb11571.x Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=138299
in American Journal of Botany > 82 (8) (1995) . - 1056-1068Susanna de la Serna, Alfonso (1955-), Garcia-Jacas, Núria, Soltis, Douglas E. (1953-), Soltis, Pamela S. (1957-) 1995 Phylogenic relationships in tribe Cardueae (Asteraceae) based on ITS sequences. American Journal of Botany, 82(8): 1056-1068.Documents numériques
article (1995)URL
Titre : The distribution of selfing rates in homosporous ferns Type de document : Imprimé Auteurs : Douglas E. Soltis (1953-) ; Pamela S. Soltis (1957-) Année de publication : 1992 Article en page(s) : 97-100 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Biologie de la reproduction
[CBNPMP-Thématique] Ptéridophytes, fougèresMots-clés : Dryopteris Résumé : The models of Lande and Schemske predict that among species in which the selfing rate is largely under genetic control and not subject to tremendous environmental variation, the distribution of selfing rates should be bimodal. When this prediction was tested empirically using data from the literature for species of angiosperms and gymnosperms, the distribution of outcrossing rates for all species was clearly bimodal. To provide another empirical test of the prediction, we analyzed mating-system data for 20 species of Pteridophyta (ferns). Homosporous ferns and their allies are unique among vascular plants because three types of mating are possible: intragametophytic selfing (selfing of an individual gametophyte); intergametophytic selfing (analogous to selfing in seed plants); and intergametophytic crossing (analogous to outcrossing in seed plants). The distribution of intragametophytic selfing rates among species of homosporous ferns is clearly uneven. Most species of homosporous ferns would be classified as extreme outcrossers. In contrast, a few species are nearly exclusively inbreeding. In only a few populations of Dryopteris expansa and Hemionitis palmata and a single population of Blechnum spicant do we see convincing evidence of a mixed mating system. The uneven distribution of selfing rates we observed for homosporous ferns, coupled with a corresponding bimodality of the magnitude of genetic load, strongly supports the model. Identifiant : DOI : 10.1002/j.1537-2197.1992.tb12628.x Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=137523
in American Journal of Botany > 79 (1) (1992) . - 97-100Soltis, Douglas E. (1953-), Soltis, Pamela S. (1957-) 1992 The distribution of selfing rates in homosporous ferns. American Journal of Botany, 79(1): 97-100.Documents numériques
article (1992)URL
Titre : The role of genetic and genomic attributes in the success of polyploids Type de document : Imprimé Auteurs : Pamela S. Soltis (1957-) ; Douglas E. Soltis (1953-) Année de publication : 2000 Article en page(s) : 310-329 Langues : Anglais (eng) Catégories : [CBNPMP-Thématique] Génétique et écologie (dynamique, démographique, sélection)
[CBNPMP-Thématique] RevégétalisationRésumé : In 1950, G. Ledyard Stebbins devoted two chapters of his book Variation and Evolution in Plants (Columbia Univ. Press, New York) to polyploidy, one on occurrence and nature and one on distribution and significance. Fifty years later, many of the questions Stebbins posed have not been answered, and many new questions have arisen. In this paper, we review some of the genetic attributes of polyploids that have been suggested to account for the tremendous success of polyploid plants. Based on a limited number of studies, we conclude: (i) Polyploids, both individuals and populations, generally maintain higher levels of heterozygosity than do their diploid progenitors. (ii) Polyploids exhibit less inbreeding depression than do their diploid parents and can therefore tolerate higher levels of selfing; polyploid ferns indeed have higher levels of selfing than do their diploid parents, but polyploid angiosperms do not differ in outcrossing rates from their diploid parents. (iii) Most polyploid species are polyphyletic, having formed recurrently from genetically different diploid parents. This mode of formation incorporates genetic diversity from multiple progenitor populations into the polyploid “species”; thus, genetic diversity in polyploid species is much higher than expected by models of polyploid formation involving a single origin. (iv) Genome rearrangement may be a common attribute of polyploids, based on evidence from genome in situ hybridization (GISH), restriction fragment length polymorphism (RFLP) analysis, and chromosome mapping. (v) Several groups of plants may be ancient polyploids, with large regions of homologous DNA. These duplicated genes and genomes can undergo divergent evolution and evolve new functions. These genetic and genomic attributes of polyploids may have both biochemical and ecological benefits that contribute to the success of polyploids in nature. Identifiant : DOI : 10.1073/pnas.97.13.7051 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=149012
in Proceedings of the National Academy of Sciences of the United States of America > 97 (13) (June 2000) . - 310-329Soltis, Pamela S. (1957-), Soltis, Douglas E. (1953-) 2000 The role of genetic and genomic attributes in the success of polyploids. Proceedings of the National Academy of Sciences of the United States of America, 97(13): 310-329.Documents numériques
Article (2000)URL
